Does radiation therapy after surgery increase survival rates?

This study investigated the benefit of combining post-operative radiation therapy with surgery and chemotherapy for the treatment of SCLC.

Small cell lung cancer (SCLC) accounts for 15% of all lung cancers. In 40% of patients SCLC is diagnosed at a limited stage (present in a single lung). The standard care given is chemotherapy (drugs used to treat cancer) and thoracic radiation therapy (using radiation to kill cancer cells in the chest); however overall survival is low because relapse (cancer returns) is common. SCLC tends to metastasise (spread) to lymph nodes and locoregional reoccurrence (cancer reoccurs at original site) is also a common issue.

Studies have shown that the best results are achieved with a combination of surgery and chemotherapy. The advantage of combining post-operative radiation therapy (radiation therapy after surgery) has however not been established.

This study aimed to identify the ability of post-operative radiation therapy to increase overall survival and reduce locoregional recurrence.

This study reviewed the records of 143 patients (71.3% male) with varied smoking backgrounds and stages of disease. All had undergone surgical procedures; lobectomy (103 patients), pneumonectomy (36), wedge excision (4). All these surgeries involve removing different parts of the lung. Post-operative radiation therapy was administered to 53 patients an average of 3 months after surgery. 58 patients received chemotherapy before surgery and 121 after surgery. The average follow up was 82 months

Overall survival rates (the percentage of patients who survived) were 79.7% at 1 year, 46.6% at 3 years and 34.6% at 5 years. The average survival time was calculated as 34 months.

Patients who received chemotherapy before surgery had a longer overall survival (96 months) than those who received chemotherapy after surgery (14 months).

Radiation therapy after surgery was found to significantly increase overall survival only in patients whose cancer had already spread to nearby lymph nodes. Overall survival was 35 months in patients with N2 cancer (cancer has spread to lymph nodes within the lung and in the space between the lungs) who did not receive radiation therapy, compared to 17 months in those patients who did.

Overall, 19.6% developed locoregional recurrence. In patients whose cancer had spread to the lymph nodes, radiation therapy after surgery significantly reduced locoregional recurrence. For example, in patients with N2 cancer, the 3-year locoregional recurrence rate was reduced from 56.6% to 4.2% with the addition of radiation following surgery.

The authors concluded that the study supports the use of radiation therapy following surgery in the treatment of SMLC that has spread to the lymph nodes.

There were varied surgical and chemotherapeutic regimes used between patients. This study reviewed records of patients (retrospective study) and therefore may have drawbacks including the potential for biased results.